Synthesis and thermoelectric properties of Nd-single filled p-type skutterudites

We report the synthesis of Nd-filled and Fe substituted p-type Ndx Fe_(3.2)Co_(0.8)Fe_(3.2)Co_(0.8)Sb_(12)(x=0.5,0.6,0.7,0.8,and 0.9)skutterudites by the solid-state reaction method.The influences of Nd filler on the electrical and thermal transport prop-erties are investigated in a temperature range from room temperature to 850 K.A lowest lattice thermal conductivity of 0.88 W·m~(-1)·K~(-1)is obtained in Nd0.8Fe_(3.2)Co_(0.8)Fe_(3.2)Co_(0.8)Sb_(12)at 673 K,which results from the localized vibration modes of fillers and the increase of grains boundaries.Meanwhile,the maximum power factor is 2.77 m W·m~(-1)·K~(-2)for the Nd_(0.9)Fe_(3.2)Co_(0.8)Fe_(3.2)Co_(0.8)Sb_(12)sample at 668 K.Overall,the highest dimensionless figure of merit z T=0.87 is achieved at 714 Kfor Nd_(0.9)Fe_(3.2)Co_(0.8)Fe_(3.2)Co_(0.8)Sb_(12).     

Complex alloying effect on thermoelectric transport properties of Cu_2Ge(Se_(1-x)Te_x)_3

To enhance the thermoelectric performance of Cu_2GeSe_3, a series of Te-alloyed samples Cu_2Ge(Se_(1-x)Te_x)_3 are synthesized and investigated in this work. It is found that the lattice thermal conductivity is reduced drastically for x = 0.1 sample, which may be attributed to the point defects introduced by alloying. However, for samples with x ≥ 0.2, the lattice thermal conductivity increases with increasing x, which is related to a less distorted structure. The structure evolution,together with the change in carrier concentration, also leads to a systemically change in electrical properties. Finally, a z T of 0.55@750 K is obtained for the sample with x = 0.3, about 62% higher than that for the pristine sample.     

金属路易斯酸催化纤维素降解为5-羟甲基糠醛

5-羟甲基糠醛(HMF)是一种重要的化学平台物质,由纤维素直接转化为HMF具有良好的应用前景。本文旨在研究金属氯化物(MClx)催化纤维素转化为HMF过程中的效率与选择性问题。以咪唑型离子液体为溶剂,通过对纤维素降解反应的时间、温度、催化剂等因素的考察和优化,发现以CrCl3.6H2O(5(mol)%)和FeCl3(5(mol)%)为复合催化剂时,120℃下反应8 h,HMF的产率可以达到55%。